We've all been there: We get on a roll, we exercise, eat well and drop some weight, but within months it's back again.
Why are our best intentions often thwarted? Researchers say it's all part of a vicious cycle fueled by stress, insomnia and depression.
Manny Sanchez, 68, is recovering from back surgery, he's fighting diabetes and it shows on the scale. But he's trying to take it all in stride.
"I call it 'creative tension.' I don't even label it stress," said Sanchez.
But whatever you call it, Kaiser Permanente researchers say people who are stressed and don't get proper sleep cannot lose weight efficiently.
"They had a harder time losing, on average, 10 pounds, than those that were less stressed, that were also less depressed, and that slept more," said Dr. Shireen Fatemi, head of endocrinology at Kaiser Permanente Panorama City.
In the study of 500 people, participants were asked to reduce their daily intake by 500 calories and get 180 minutes of weekly exercise.
Those who reported high levels of insomnia, stress and depression were less likely to get to their goal of losing 10 pounds.
Fatemi says some of the reasons are obvious.
"If you are stressed and you are not sleeping, you are eating more," said Fatemi.
There's a metabolic reason for this as well: If you're stressed out and not sleeping, your body produces more cortisol, and that causes your glucose and insulin production to go up, and that causes your body to hang onto fat.
"You go into a cycle where you're preserving more energy rather than expending it," said Fatemi. "You're building it up more."
Fatemi says what this study shows is that people who want to lose weight need to do more than just diet and exercise. They need to manage their stress. It not only helps with the initial weight loss, but it can help folks like Manny Sanchez keep the pounds off for good.
"I find that music, exercise and laughter -- put on a comedy show, and things like that -- really help me a lot," said Sanchez.
Also in the study, Kaiser researchers found people who slept more than eight hours a night were less likely to lose weight. Fatemi says it may be because people who tend to sleep a lot may be dealing with stress and or depression.